1. Field of the Invention
This invention relates to electromagnetic circuit technology and more particularly to the design of termination devices used in coupled cavity traveling wave tubes (TWTs).
2. Prior Art
Prior art termination devices include the common wedge device. The device may be comprised of a lossy ceramic and positioned within the termination chamber such that the thick portion of the wedge is located at the radially outer portion of the chamber and the edge of the wedge is proximate the central aperture of the chamber. The exterior dimensions of the wedge are chosen such that the wedge conforms to the interior dimensions of the termination chamber. A single such wedge placed inside the termination chamber serves to provide a termination match for the traveling wave tube. A typical TWT termination chamber provided with such a termination device will, nonetheless, exhibit a certain amount of small signal gain variation, phase ripple and amplitude modulation to phase modulation conversion. It is obviously desirable to minimize all such distortions occurring in the termination chamber. Accordingly, it is an object of the present invention to provide a TWT termination device that significantly reduces such distortions and improves the performance of the TWT and its termination assembly as a whole.
Some relevant patents, which may serve to illustrate the evolution of termination device design, include U.S. Pat. Nos. 2,985,792, 3,123,736 and 3,181,023. These patents show internal termination (i.e., internal to the chamber), external termination, and hybrid termination, respectively. The latter patent also shows use of a single wedge termination the specific shape of which is set forth at Column 6, lines 3-39. A copy of U.S. Pat. No. 3,181,023 is enclosed.